196 The Ottawa Naturalist. [December 



A SIMPLE ILLUSTRATION OF THK CONSERVATION 



OF ENERGY. 



By J. C. Sutherland, B.A. , Richmond, Que. 



The other day when blowpiping- some silver nitrate on the 

 "charcoal splinter," I observed what seemed to be a good, 

 although simple, illustration of the law of the conservation of 

 energy. It is possible that the phenomenon has been observed 

 many times before, but I cannot recall any instance of the parti- 

 cular explanation which I believe to be the correct one having 

 been offered for it. 



As possibly some readers may not be acquainted with the 

 reduction process which is carried on by means of a charcoal 

 splinter, it may be well to give a brief account of it before pro- 

 ceeding to the particular phenomenon and the offered explanation. 



To prepare a charcoal splinter, the head of a common match 

 is broken off and the wood is then smeared for about an inch of 

 its length with ordinary washing soda melted in the flame of a 

 spirit lamp. The smeared end is then gently heated in the flame 

 for a few moments until a charred mass of wood and soda is ob- 

 tained. Upon this is placed carefully a small mass of the particu- 

 lar substance to be reduced, mixed with some fused soda. The 

 blowpipe is then directed on the flame, the mass being held in the 

 "reduction" part of it. In a few minutes separation of the 

 elements is obtained, and in the case of silver nitrate a beautiful 

 small sphere of metallic silver is left upon the splinter. 



Buc in the first few seconds of the operation, the unsmeared 

 part of the match tends to burst into flame. C^nce, however, that 

 the reduction process is fully started, this does not occur. This 

 is the phenomenon. What is the explanation? 



It is possible that in some instances, and then in part only, it 

 is due to the formation of combustible gases at the outset which 

 cease to be formed as the reduction proceeds. But I think the 

 more general explanation of the fact is to be found in the consider- 

 ation that during the first few seconds of the blowpiping, the only 

 work that is done by the flame is that of raising the temperature 

 of the mass and driving off" moisture — comparatively light work 



